render animation with alpha

[pavel]

Is it possible to save my animation as quicktime or avi with alpha hdri? I want the hdri to cast light on my object but not to be visible in the animation. I know that i can have that if i save as png, but does it work with quicktime or avi? Thanks

[pavel]

Can someone please give me a tip on how to do this? Can i animate with alpha background, light my scene with a hdri and save the animation as quicktime or avi? Thank you.

[aoktar]

i'm not sure that understand exactly you. You can save outputs whatever you want. But did you tried to do something or checked in liveviewer? Kernels has "enable alpha" and "keep environment" options. this is the ways to get images with alpha. What is the alpha with hdri?

[bepeg4d]

hi pavel,
as far as i know, quicktime can save a .mov with alpha only with the "animation" codec, sorry i don't know anything about avi
ciao beppe

[cleanerxx]

uncompressed avi supports alpha channel too.
but why wouldn´t someone use image sequences?

[pavel]

Somehow i forgot to uncheck keep background, and now i do not see the hdri anymore, which is good, but i have a black background instead of alpha. I have tried both quicktime animation and avi unconpressed.

I have attached the scene, in case anyone has time to check it. Sorry guys, i am sure it's very easy but i am pretty new to 3D and i don't know much.

Thanks

[kiwimage]

As people already said to you, you should make an image sequence (png with RGBA enabled, or maybe .tif),

Then in After effects or any video editing package, you can import this images sequence and render it as quicktime movie ( with "animation" codec, that indeed supports alpha channels).

Using sequences is a good practice because you separate the 3d rendering and video encoding tasks.

[slepy8]

Render the whole scene normally with HDRI.
Than turn off octane render in settings, get rid of HDRI and do a separate alpha. This render will take you few minutes/secconds.

In any kind of compositing program you'll be able to use the alpha map for your footage.

Or use multipass.